the thing keeps doin it

bills '94 850 · Post by **bills '94 850** » 16 Apr 2005, 02:13

(850 continually shuts down engine).
Remember that thread? Well, I have discounted the fuel pump being faulty by checking to see if there is pressure in the fuel rack (that was described in here before too). After shut down, some fuel still spits out.
I disconnected the sensor on the air filter box, both when running or starting after being stopped. It made no difference to anything. Should it do something? The next disconnect was the idle motor. It started ok, then It ran ok but for an slight increase in rpm. I let it run and reconnected while running- it shut down. Disconnected it starts up. Test drive- while disconnected-didn't stall on idle when pulling up. Died while on the move. I checked each sensor on the efi and each one had an effect on how the engine ran.
Q / ???? The MAF is another word for the air filter box isn't it? What should happen when u disconnect that sensor?

Can the idle motor affect the car in motion? Normal rpm 1700 at 60/70kmh. Any more clues out there?

HHEEELLLLPPPPPP

I need some more help.

Could it be electrical? where do I start to look?

Any comments appreciated.

White850Turbo · Post by **White850Turbo** » 16 Apr 2005, 05:35

You said that after shut down, you can still get fuel to come out of the schraeder valve. If so, that's a darn good sign of a faulty fuel pressure regulator. MAF stands for Mass Airflow Sensor. It simply measures the amount of air entering the turbo/manifold and it's signal is used by the ECU along w/ others such as the throttle position sensor to determine fuel trim. It's not the same thing as the air filter box, but can be found on the air intake pipe. If you remove it while running on the turbo cars, the car will die, but it will stay running for some reason on the N/A cars.

bills '94 850 · Post by **bills '94 850** » 17 Apr 2005, 02:04

thanks whitey.
I tried that schraeder valve when the engine is running to see what sort of pressure there was. You get a good continual spurt. When the engine dies and the valve is checked, there is a quick spit of fuel that I suppose is the last of the pressure that was in the fuel system, then nothing. What's the norm?
Lastly, is the fuel pressure regulator the one near the fan shroud. I changed that one to see if it would stop, and it still did. Mind u it was 2nd hand, but no change to the running.
Are you familiar with the idle motor? It has a sensor and when disconnected it ran ok, but when u re-connected, it died. If u waited a while after stall, connected it before start it would run fine at idle for a while. I didn't know if that part is relative to a shut down while at normal suburb speed.

AJU · Post by **AJU** » 18 Apr 2005, 07:47

The IAC (idle air controller) allows air to flow into the engine when the throttle plate is closed. If you are cruising at low rpms and snap the throttle plate shut and the IAC doesn't allow air in, you might have a stall.